Answer: To create a buffer zone against future invasions.
Explanation/context:
The Soviet Union believed they needed a buffer against possible future invasions from Western Europe. Remember, the Soviet Union had been invaded by Germany in World War II and suffered millions of casualties in that war.
The focus of the Western members of the Allies was on allowing free and democratic elections in the nations of Europe after the war. When Roosevelt, Churchill and Stalin, leaders of the World War II Allied nations, met at Yalta in 1945, there was a big push for Stalin to allow free elections to take place in Eastern European nations after the occupying armies of Germany were defeated. At the Yalta Conference, Stalin agreed, but there was a strong feeling by the other leaders that he might renege on that promise. The Soviets never did allow those free elections to occur. Later, Winston Churchill wrote, ""Our hopeful assumptions were soon to be falsified." Stalin and the Soviets felt they needed the Eastern European nations as satellites to protect their own interests.
